2-Ethylbutyraldehyde → 1,3-Dioxepin, 2-(1-ethylpropyl)-4,7-dihydro-

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Reaction Steps

To a one liter flask equipped with heating jacket, agitator and condenser fitted with a Dean-Stark trap was charged 100 grams (1.0 mole), 2-ethyl-butanal, 97 grams(1.1 mole) 2-butene-1,4-diol, 80 grams cyclohexane and 0.2 grams p-toluenesulfonic acid monohydrate. The mixture was heated with vigorous agitation at reflux (84° - 99°C.) until water no longer continued to be distilled from the reaction mixture (1.2 hours). The reaction mixture was cooled to room temperature and the p-toluenesulfonic acid neutralized by washing with reaction mixture with a 5% aqueous solution of sodium hydroxide. The reaction mixture was then washed neutral with water and distilled to remove the cyclohexane. The oil was vacuum distilled to obtain 146 grams (86% of theoretical) of 4,7-dihydro-2-(3-pentyl)-1,3-dioxepin having a boiling point of 47°C. at a pressure of 1.0 millimeter of mercury, (refractive index, ND20 = 1.457). Analysis for carbonyl content of IR showed 0.0% carbonyl and VPC analysis showed the compound to have a purity of 100%.

Provenance & Evidence